Thermostat switch



THERMOS TAT SWI TCH Filed Feb. 25, 1925 Patented Feb. 11, 1930 UNITED STATES ,PATENT OFFICE DAVID GRAY, F PORTLAND, MAINE THERMOSTAT SWITCH Application led February 25, 1928. Serial No. 256,872.

ment which serves to move a spring alternately in opposite directions to cause a sna action in making and breaking the electric circuit controlled by the switch.

A further object is to provide a switch in which the spring is not included in the electric circuit.

A further object is to provide a switch of exceptionally sensitive action, and of simple construction.

Referring to the drawings which form a part of this specification,

Fig. l, is a plan view of a switch embodying my invention, showing the switch in its closed circuit position.

Fig. 2, is a plan view showing the switch in its open circuit position just after the switch has operated to break the circuit.

Fig. 3, is a longitudinal sectional view taken on the median line indicated by the arrows as indicated in Fig. 1.

Fig. 4, is a cross sectional view taken on line 4 4 of Fig. 1.

Fig. 5, is a cross sectional view taken on line 5 5 of Fig. l.

A, indicates a base-plate of insulating `material such as hard rubber, which is recessed on its underside to receive the screw heads of the screws used to hold the parts of the switch to the base-plate, the said recesses and screw heads being indicated in dotted lines A1. K

The base-plate is also provided with a recess `=..2 in its upper side, the longitudinally extending side walls of which serve as abutments to limit the movement of the switch in its action in making and breaking the circuit. B, indicates an L-shaped metal clip which is secured to the base-plate by a screw B1, and which is provided with a hole throughits upwardly extending portionthrough which a. binding screw C, extends and servesto clamp the bi-metallic thermostat elements, D, to the clip in fixed relation by means of a nut E, the lower edge of the thermostat being held {irmly against the upper surface of the clip, B,

and thus preventing any upward swinging movement of thethermostat. A binding nut, F is also screwed onto the shank of the screw, C, to provide a terminal for one end of the wire, Gr, conducting the electric current, and

p by this arrangement of parts the construction is simplified. Y

The thermostat, D, is preferably made of two straight strips', one of brass and one of iron secured together in the usual manner, and appears as shown in FigJ/l, when a normal quantity of electricity is flowing therethrough.

H, indicates a cage formed of sheet metal, i and comprising a rectangular shaped arm 55 portion H1, the short end H2, of which is provided with wing portions H2, Which'are bent over the top and bottom edges of the thermostat, D, to clamp the arm portion H2, to the free end of the thermostat, D. The cage, H, is formed integral with the opposite end of the arm H1, one side of which is formed with a contact surface,`I. The cage is substantially U-shaped in form and its oppositely disposed side walls serve to swing a sti lever, J, which cooperates with a spring, N, in the movement of the switch.

K, indicates a metal bracket which is held firmly to the base-plate by a screw and nut,v

construction indicated by K1 and K2, respec- 80 tively, and a binding nut K3 is screwed on the shank of the screw K2,to hold the end of the wire, L. A pin, M, extending through the bottom ofthe bracket, K, into the baseplate prevents any rotational movement and serves to position the bracket on the baseplate. The bracket, K, is formed with an upwardly extending L-shaped portion, M1, having a slot M2, in its crotch, through which extends a projection J1, formed on the end of the lever J, to prevent the'lever from rising or falling at this point while permitting it to abut the surface of the crotch and swing laterally, as will be readily understood.

The opposite end of the lever, J, is located between the upwardly extending side walls of the cage, H, and is bent to form a V-shaped abutment for a small leaf spring, N, of steel or other suitable spring material, while one side is provided with side clip portionsJ 2, J 2,

respectively, which are bent over and hold" a piece o'f insulating material O, to prevent short-circuiting the current when the switch is in its open position.

P, indicates an L-shaped clip, the base-plate portion of which is secured to the base-plate A, by a nut and screw combination, R, and vits upper end is bent over as shown at P1, to hold the end N1, of the spring, N, firmly in position. The length of the spring, N, is slightly greater than the distance from the crotch, J 4, of the lever J, when said lever and spring are in alignment and therefore the spring must buckle or -bend slightly to permit the cage to move the lever, J, past the median line of the' l ther means of support, and permits the lever,

J, to be quickly placed in position or removed. By locating the bottom end of the cage, I-I, in the recess, A2, as illustrated, the movement of the cage is restricted in both directions and danger of displacement of the parts is practically obviated.

The switch operates as follows:

Assuming the circuit to be closed as shown in Fig. 1, the current flows through wire, G, to screw, C, thence through thermostat, D, and arm, H, through contact point, I, to lever, J, and bracket, M, to the wire, L, until the heat governing the thermostat rises above normal, when the thermostat will bend to the position illustrated in Fig; 2, causing. the cage, H, to swing laterally and flexing the spring, N, until it snaps over across the median line and instantly breaks the circuit.

When the thermostat cools it swings the cagev back, causing a reverse action of that just described and again connects the circuit.

Having thus described my invention I claim as new:

1. A thermostat controlled switch, comprising a thermostat, a cage carried thereby having a contact point thereon, a lever movable by said cage having a contact point thereon, and a spring abutting said lever adapted to be flexed by the movement of the cage to make and break an electric circuit passing thru said lever and cage.

2. A thermostat controlled switch comprising a base-plate, a `clip secured thereto, a thermostat held by'said clip, a cage carried by the free end of said thermostat, said cage having oppositely disposed walls, a lever having one end disposed between said walls tween, means for insulating the lever from one of said walls and means for effecting contact between said lever and the other said wall a spring held in abutting relation with the free end of said'lever and means for supporting'its opposite end in swinging position.

3. A thermostat controlled switch' comprising a base-plate, a clip secured thereto, a thermostat held to said clip by a screw which also serves as a binding-post for one terminal of the switch, a cage carried by the free end of 'the thermostat said cage having upwardly extending oppositely disposed side walls, a lever having one end disposed between said walls and of less width than the ldistance therebetween, one side of which is adapted to contact with one of said walls to make electrical contact, and the opposite said wall being insulated to prevent electrical contact, a spring-supported from said base-plate and one end and abutting the free end of said lever at its opposite end, a bracket secured to said base-plate and having an upwardly ex-l tending portion with a crotch having a slot formed therein, one end of said lever resting in said crotch and having a projection extending thru said slot.

4. As set forth in claim 3, and means for limiting the movement of said cage in its swinging action.

5. An electric switch comprising a bimetallic leaf thermostat, a cage carried thereby having spaced walls andan electric contact point fixed on one of said walls, a spring and lever movable by said cage to open and close an electric circuit leading thru said thermostat, cage and lever, by a snap action as set forth, said lever having a contact point to engage the point carried by the cage.

6. As set forth in claim 5; and means for-,restricting the movement'of said cage.

7. An electric switch comprising a baseplate, a clip mounted thereon, a thermostat carried by said clip, a cage carried by said thermostat, a bracket, a lever abutting said bracket in swinging relation thereto, said lever having a crotch formed in one end thereof, a spring abutting said crotch and adapted to move said lever and cage with a snap action in breaking a circuit leading thru said thermostat, cage and lever; and insulating means between one side of said lever and cage.

8. An electric switch comprising a baseplate, a thermostat supported thereon, a cage carried thereby having a contact point, a lever having a contact point to abut the contact point carried by the cage, a spring abutting said lever, said cage and lever being movable together while holding the contact points in abutment until the device acts to break the circuit.

In testimony whereof I have aiixed my signature.

' DAVID GRAY. 

